Dr. Bailey-Wilson is a member of a collaborative study of Attention Deficit Hyperactivity Disorder, collaborating with Drs. Max Muenke and Kate Berg of NHGRI. Dr. Bailey-Wilson's role is to help with study design and to serve as statistical geneticist on the project. In the past, we have performed power studies of many large pedigrees from Columbia, showing that there will be adequate power in a future linkage study to detect genes of moderate to large effect, even in the presence of heterogeneity. In this fiscal year, we have performed additional simulations, showing the predicted power of pedigrees for which biological sampling and phenotyping has been completed. Dr. Bailey-Wilson also advises the other collaborators about the types of pedigree structures that are particularly informative for linkage studies. This study is ongoing. A paper detailing the study design and the simulation results is in preparation, and these results have been presented at scientific meetings in this fiscal year.